Capacitive sensors for electronic devices and methods of forming the same

ABSTRACT

Capacitive sensor assemblies for electronic devices, and methods of forming capacitive sensor assemblies. The capacitive sensor assembly may include a top component having an intermediate layer formed on the top component, a bottom component positioned opposite the top component, a silicone layer positioned between the top component and the bottom component, and a first electrical trace positioned adjacent the silicone layer.

TECHNICAL FIELD

The disclosure relates generally to electronic sensors, and more particularly to capacitive sensor assemblies for electronic devices, and methods of forming the capacitive sensor assemblies.

BACKGROUND

Conventional electronic devices typically include a variety of distinct input devices formed from a plurality of components. For example, conventional electronic devices typically include a touch display to allow a user to interact with the device. Touch displays typically include a plurality of sensor assemblies that may be positioned inside the casing of the electronic device. The sensor assemblies may be used to detect when a user touches an external surface of the electronic device with the desire to interact with the device. When the sensor assemblies detect a user's touch, the sensor assemblies may send an electrical input signal to distinct portions of the electronic device.

Conventional sensor assemblies include a plurality of layers and/or components to detect the user's touch or interaction with the electronic device. However, as the number of layers and/or components increase in the sensor assemblies, so does the required space for housing the assembly within the electronic device. That is, as the number of layers and/or components increase in the sensor assemblies, the over height and/or z-space of the sensor assemblies also increases.

Additionally, a bond must be formed between all layers and/or components of the conventional sensor assemblies. With an increase in the layers and/or components, the likelihood of a bonding of the assembly to come undone or uncoupled increases. Where two layers or components of the sensor assembly come uncoupled, the sensor assembly may have reduced operational function, or may become inoperable.

SUMMARY

Generally, embodiments discussed herein are related to electronic sensors, and more particularly to capacitive sensor assemblies for electronic devices, and methods of forming the capacitive sensor assemblies. The capacitive sensor assemblies discussed herein may reduce the number of layers and/or components forming the assembly by utilizing a silicone layer positioned between electrical traces, and/or forming the electrical traces within or out of pre-existing layers of the electronic device. By utilizing a silicone layer within the capacitive sensor assembly, a strong bond may be formed between the silicone layer and the distinct layers and/or components of the capacitive sensor assembly and/or components of the electronic device. Additionally, by forming the electrical traces of the capacitive sensor assembly within or out of pre-existing layers of the electronic device, the number of layers or components of the capacitive sensor assembly may be reduced, and the height or z-space of the capacitive sensor assembly may be reduced. As a result of the reduce number of layers or components, the risk of operational fault or failure may be reduced or eliminated. Additionally, as a result of the reduced height of the capacitive sensor assembly, the overall height and size of the electronic device implementing the capacitive sensor assembly may also be reduced.

One embodiment may take the form of a method of manufacturing a capacitive sensory assembly in an electronic device. The method may comprise coupling a silicone layer to a bottom portion of a housing of the electronic device, positioning a first electrical trace within a flex layer, the flex layer positioned on the silicone layer, opposite the bottom portion of the housing, and curing the silicone layer to the flex layer including the first electrical trace. The method may also comprise applying an adhesive to the flex layer including the first electrical trace, opposite the silicone layer, and coupling a cover of the electronic device to the flex layer using the applied adhesive.

An additional embodiment may take the form of a method of manufacturing a capacitive sensory assembly in an electronic device. The method may comprise coupling an intermediate layer on a at least a portion of an inner surface of a cover of the electronic device, etching a portion of the intermediate layer to form a first electrical trace in the etched portion, positioning a silicone layer between the intermediate layer and a bottom portion of a housing of the electronic device, and curing the silicone layer to the intermediate layer including the first electrical trace.

Another embodiment may take the form of an electronic device comprising a housing having a top portion, and a bottom portion coupled to the top portion. The electronic device may also comprise a capacitive sensor assembly positioned within the housing. The capacitive sensor comprises a silicone layer positioned between the top portion and the bottom portion of the housing, a flex layer coupled to the silicone layer, and a first electrical trace positioned within the flex layer.

A further embodiment may take the form of an electronic device comprising a housing, a cover glass coupled to the housing, an intermediate layer formed on an inner surface of the cover glass, and a capacitive sensor assembly positioned between the housing and the cover glass. The capacitive sensor comprising a silicone layer coupled to the intermediate layer formed on the inner surface of the cover glass, and a first electrical trace positioned within the intermediate layer, adjacent the silicone layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which:

FIG. 1 depicts an illustrative perspective view of a portion of a wearable electronic device, according to embodiments.

FIG. 2 depicts an illustrative cross-section side view of a portion of the electronic device of FIG. 1 including a capacitive sensor assembly, taken along line CS-CS, according to embodiments.

FIG. 3 depicts a flow chart of an example process for forming a capacitive sensor assembly for an electronic device, according to embodiments.

FIGS. 4A-4D depict illustrative cross-section side views of a portion of the electronic device of FIG. 1 and various components of a capacitive sensor assembly undergoing the process depicted in FIG. 3, according to embodiments.

FIG. 5 depicts an illustrative cross-section side view of a portion of the electronic device of FIG. 1 including a capacitive sensor assembly, taken along line CS-CS, according to additional embodiments.

FIG. 6 depicts a flow chart of another example process for forming a capacitive sensor assembly for an electronic device, according to additional embodiments.

FIGS. 7A-7D depict illustrative cross-section side views of a portion of the electronic device of FIG. 1 and various components of a capacitive sensor assembly undergoing the process depicted in FIG. 6, according to additional embodiments.

FIG. 8 depicts an illustrative cross-section side view of a portion of the electronic device of FIG. 1 including a capacitive sensor assembly, taken along line CS-CS, according to further embodiments.

FIG. 9 depicts a flow chart of an additional example process for forming a capacitive sensor assembly for an electronic device, according to further embodiments.

FIGS. 10A-10C depict illustrative cross-section side views of a portion of the electronic device of FIG. 1 and various components of a capacitive sensor assembly undergoing the process depicted in FIG. 9, according to further embodiments.

It is noted that the drawings of the invention are not necessarily to scale. The drawings are intended to depict only typical aspects of the invention, and therefore should not be considered as limiting the scope of the invention. In the drawings, like numbering represents like elements between the drawings.

DETAILED DESCRIPTION

Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims.

The following disclosure relates generally to electronic sensors, and more particularly to capacitive sensor assemblies for electronic devices, and methods of forming the capacitive sensor assemblies.

The capacitive sensor assemblies discussed herein may reduce the number of layers and/or components forming the assembly by utilizing a silicone layer positioned between electrical traces, and/or forming the electrical traces within or out of pre-existing layers of the electronic device. By utilizing a silicone layer within the capacitive sensor assembly, a strong bond may be formed between the silicone layer and the distinct layers and/or components of the capacitive sensor assembly and/or components of the electronic device. Additionally, by forming the electrical traces of the capacitive sensor assembly within or out of pre-existing layers of the electronic device, the number of layers or components of the capacitive sensor assembly may be reduced, and the height or z-space of the capacitive sensor assembly may be reduced. As a result of the reduce number of layers or components, the risk of operational fault or failure may be reduced or eliminated. Additionally, as a result of the reduced height of the capacitive sensor assembly, the overall height and size of the electronic device implementing the capacitive sensor assembly may also be reduced.

These and other embodiments are discussed below with reference to FIGS. 1-10C. However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these Figures is for explanatory purposes only and should not be construed as limiting.

FIG. 1 shows an illustrative perspective view of a portable or wearable electronic device 100 (hereafter, “electronic device”), according to embodiments. Electronic device 100, as shown in FIG. 1, may be configured to provide health-related information or data such as but not limited heart rate data, blood pressure data, temperature data, oxygen level data, diet/nutrition information, medical reminders, health-related tips or information, or other health-related data. The electronic device may optionally convey the health-related information to a separate electronic device such as a tablet computing device, phone, personal digital assistant, computer, and so on. In addition, electronic device 100 may provide additional information, such as but not limited to, time, date, health, statuses or externally connected or communicating devices and/or software executing on such devices, messages, video, operating commands, and so forth (and may receive any of the foregoing from an external device), in addition to communications.

Electronic device 100 may include a housing 102 at least partially surrounding a display 104 and one or more buttons 106 or input devices. The housing 102 may form an outer surface or partial outer surface and protective case for the internal components of electronic device 100, and may at least partially surround the display 104. The housing 102 may be formed of one or more components operably connected together, such as a front piece and a back piece. Alternatively, the housing 102 may be formed of a single piece operably connected to the display 104. Housing 102 may formed from a plurality of distinct materials including, but not limited to: corundum, commonly referred to as sapphire, glass or plastic. As discussed herein, and in another example, housing 102 may be formed from an electrically conductive material, or a material having electrically conductive properties.

Display 104 may be implemented with any suitable technology, including, but not limited to, a multi-touch sensing touchscreen that uses liquid crystal display (LCD) technology, light emitting diode (LED) technology, organic light-emitting display (OLED) technology, organic electroluminescence (OEL) technology, or another type of display technology.

Button 106 may include any conventional input/output (I/O) device for electronic device 100. Specifically, button 106 may include an actuation component in electronic and/or mechanical communication with the internal components of electronic device 100, to provide user input and/or allow the user to interact with the various functions of electronic device 100. In an embodiment button 106 may be configured as a single component surrounded by housing 102. Alternatively, button 106 may include a plurality of components, including an actuation component, in mechanical/electrical communication with one another and/or internal component of electronic device 100. Button 106 may likewise include a sensor, such as a biometric sensor, touch sensor, or the like.

Housing 102 may also have recesses 108 formed on opposite ends to connect a wearable band 110 (partially shown in FIG. 1) to electronic device 100. Wearable band 110 may be used to secure wearable electronic device 100 to a user, or any other object capable of receiving electronic device 100. In a non-limiting example where electronic device 100 is a smart watch, wearable band 110 may secure the watch to a user's wrist. In other non-limiting examples, electronic device 100 may secure to or within another part of a user's body.

A cover 112 may be positioned above the touchscreen of display 104. That is, and as discussed herein, cover 112 may be positioned above the touchscreen of display 104 and may be at least partially positioned within an opening of housing 102 and coupled to housing 102. Cover 112 may protect display 104 from containments, without obstructing a user's view and/or ability to interact with display 104 and/or electronic device 100. As such, cover 112 may be transparent or translucent, fully or partially, in certain embodiments. As discussed herein, cover 112 may be formed corundum, commonly referred to as sapphire. However, it is understood that cover 112 may be formed from any suitable transparent material and/or combination of suitable transparent material including, but not limited to, ceramics, alumina, chemically strengthened glass, and reinforced plastic.

FIG. 2 depicts an enlarged cross-section front view of a portion of electronic device 100 of FIG. 1 taken along line CS-CS, according to an embodiment. With respect to this particular embodiment, FIG. 2 shows a cross-section front view of a portion of housing 102 and cover 112 of electronic device 100. Electronic device 100 may also include an intermediate layer 118 formed on at least a portion inner surface 120 of cover 112. Intermediate layer 118 formed on cover 112 may be positioned within an opening 122 formed between cover 112 and housing 102, and may not be exposed in electronic device 100. Intermediate layer 118 may be optically dense and/or substantially translucent or opaque, such that a user of electronic device 100 may not be able to see through the portion of cover 112 positioned above intermediate layer 118. In a non-limiting example shown in FIG. 2, and as a result of the optical properties, intermediate layer 118 may be positioned around a perimeter of cover 112 to define an interactive area of electronic device 100, adjacent the intermediate layer 118. The interactive area of electronic device 100 may include the touch screen of display 104 (see, FIG. 1), as discussed herein.

Intermediate layer 118 may be formed from a variety of materials. In a non-limiting example, intermediate layer 118 may be formed from an ink material. The ink material may be deposited on inner surface 120 of cover 112 using any suitable deposition technique or process including, but not limited to, painting, spraying, mask-and-ink submersion and the like. In another non-limiting example, intermediate layer 118 may be formed as a substantially solid material layer. In the non-limiting example, the substantially solid material layer may be formed as a plastic layer that may be coupled to inner surface 120 of cover 112. The plastic layer may be coupled to the inner surface 120 using any suitable coupling technique or process (e.g., bonding, welding, melting, and so on).

Electronic device 100 may also include a capacitive sensor assembly 124 positioned within housing 102. In a non-limiting example shown in FIG. 2, capacitive sensor assembly 124 may be substantially positioned between cover 112 and a bottom portion or component 126 of housing 102. As discussed herein, bottom portion or component 126 may be formed from distinct material and/or a distinct component than the remainder of housing 102. Capacitive sensor assembly 124 may be in electrical communication with display 104 and/or additional components of electronic device 100, and may be configured to detect input provide to electronic device 100 via cover 112. That is, when a force is applied to outer surface 128 of cover 112 to interact with display 104 (see, FIG. 1) and/or other components of electronic device 100, cover 112 may substantially deflect and/or flex toward bottom portion or component 126 of housing 102. As a result, capacitive sensor assembly 124 may sense or detect the deflection of cover 112 to provide an input to electronic device 100.

Capacitive sensor assembly 124 may include a silicone layer 130 positioned within opening 122 of electronic device 100. Silicone layer 130 may be positioned between intermediate layer 118 formed on inner surface 120 of cover 112 and housing 102, and in the non-limiting example shown in FIG. 2, silicone layer 130 may be coupled directly to bottom portion or component 126 of housing 102. As discussed herein, silicone layer 130 may be coupled to bottom portion or component 126 using any suitable coupling technique including, but not limited to, injection molded, cured, adhered or the like. In certain embodiments, the silicone layer 130 may mechanically couple adjacent layers to one another, such as the adjacent layers shown in FIG. 2 and subsequent figures, such as bottom component 126 and flex layer 132.

Silicone layer 130 may also be substantially compliant, flexible and/or elastic. As a result, when a force is applied to cover 112, silicone layer 130 may substantially deform to allow electrical traces of capacitive sensor assembly 124 to move toward each other to vary a capacitance between the traces, and ultimately generate an electrical signal to be sent to electronic device 100 based on the applied force, as discussed herein. Additionally, the physical properties compliance and/or elasticity of silicone layer 130 may allow portions of capacitive sensor assembly 124 (e.g., electrical traces) to return to a neutral state (e.g., “spring-back” to an uncompressed position) relatively rapidly, thereby permitting the detection of a consecutively-applied forces being applied to cover 112 of electronic device 100. Further, and as discussed herein, silicone layer 130 may be positioned between two electrical traces of capacitive sensor assembly 124 to separate the traces in order to detect the force applied to cover 112.

Capacitive sensor assembly 124 may also include a flex layer 132. In a non-limiting example shown in FIG. 2, flex layer 132 may be positioned between silicone layer 130 and intermediate layer 118. As discussed herein, flex layer 132 may be bonded and/or coupled to silicone layer 130 of capacitive sensor assembly 124 using a variety of coupling or bonding techniques (e.g., adhesive, curing, and so on). Additionally, an adhesive 134 may be used to couple flex layer 132 to intermediate layer 118 of electronic device 100. In the non-limiting example shown in FIG. 2, adhesive 134 may be a pressure sensitive adhesive that may completely cover flex layer 132 and may be positioned between flex layer 132 and intermediate layer 118 to couple or bond flex layer 132 to cover 112 via intermediate layer 118. The use of adhesive 134 to bond flex layer 132 to intermediate layer 118 and/or cover 112, as well as the other connections, couplings and/or bonds formed between the various layers or components of capacitive sensor assembly 124, may result in a hermetic seal being formed within electronic device 100.

Similar to silicone layer 130 of capacitive sensor assembly 124, flex layer 132 may include substantially compliant, flexible and/or elastic properties. In a non-limiting example, flex layer may be formed from an elastomeric material. As a result, and as discussed herein with respect to silicone layer 130, when a force is applied to cover 112, flex layer 132 may also deform and/or flex toward bottom portion or component 126. Additionally, when the force on cover 112 is removed or discontinued, flex layer 132 may return or “spring-back” to a neutral state (e.g., uncompressed position).

A first electrical trace 136 may be positioned or formed within flex layer 132 of capacitive sensor assembly 124. In a non-limiting example shown in FIG. 2, first electrical trace 136 may be positioned within flex layer 132 coupled to silicone layer 130, such that first electrical trace 136 may be positioned between silicone layer 130, and intermediate layer 118 and/or cover 112 of electronic device 100. First electrical trace 136 may have capacitive characteristics and/or first electrical trace 136 may be formed from an electrically conductive material, for example copper. Although only a single first electrical trace 136 is shown in FIG. 2, it is understood that capacitive sensor assembly 124 may include a group of electrical traces forming first electrical trace(s) 136.

In the non-limiting example shown in FIG. 2, and as discussed herein, first electrical trace 136 may be a driven capacitive trace that may cooperate with an additional electrical trace of capacitive sensor assembly 124 to detect a force applied to cover 112 of electronic device 100 by measuring changes in capacitance between the cooperating electrical traces of capacitive sensor assembly 124. By measuring the changes in capacitance, capacitive sensor assembly 124 may detect the force applied to cover 112 and may subsequently provide an electrical signal to display 104 and/or additional components of electronic device 100, as discussed herein.

As discussed herein, bottom portion or component 126 of housing 102 may be formed from a distinct component or material from the remainder of housing 102 of electronic device 100. Where capacitive sensor assembly 124 includes only a single electrical trace (e.g., first electrical trace 136) formed between cover 112 and bottom portion or component 126 of housing 102, bottom portion or component 126 may form a cooperating electrical trace for first electrical trace 136. In a non-limiting example shown in FIG. 2, bottom portion or component 126 of housing 102 may be formed from an electrically conductive material (e.g., copper) and may provide a cooperating electrical trace structure for first electrical trace 136. Where first electrical trace 136 forms a driven capacitive trace, bottom portion or component 126 may form a sense capacitive trace that may cooperate with first electrical trace 136.

First capacitive sensor assembly 124 may detect a force applied to cover 112 by measuring the change in capacitance between first electrical trace 136 and the cooperating electrical trace formed by bottom portion or component 126 of housing 102. In a non-limiting example, a continuous charge or current may be provided to both first electrical trace 136 and bottom portion or component 126. The charge or current may provide a predetermined steady-state or uncompressed, measurable capacitance between first electrical trace 136 and bottom portion or component 126. When a force is applied to cover 112 of electronic device 100, cover 112, flex layer 132 and/or silicone 130 may deflect and/or may flex toward bottom portion or component 126 of housing 102, as discussed herein. This may also cause first electrical trace 136 to deflect toward bottom portion or component 126 of housing 102, resulting in the distance and the capacitance between first electrical trace 136 and bottom portion or component 126 to change. When the capacitance between first electrical trace 136 and bottom portion or component 126 changes, capacitive sensor assembly 124 may detect that a force has been applied to cover 112, and may subsequently send an electrical signal to display 104 and/or distinct components of electronic device 100.

FIG. 3 depicts an example process for forming a capacitive sensor assembly for an electronic device. Specifically, FIG. 3 is a flowchart depicting one example process 200 for forming a capacitive sensor assembly having cooperating electrical traces formed from a first electrical trace and an electrically conductive housing. In some cases, process 200 may be used to form one or more capacitive sensor assemblies, as discussed above with respect to FIG. 2.

In operation 202, a silicone layer is coupled or bonded to a bottom portion or component of a housing. In operation 204, a first electrical trace may be positioned within a flex layer positioned on the silicone layer. In operation 206, the silicone layer may be cured or bonded to the flex layer including the first electrical trace. In operation 208, an adhesive may be applied to the flex layer including the first electrical trace. In operation 210, a cover or top portion or component of the housing may be adhered to the flex layer using the applied adhesive.

FIGS. 4A-4D show capacitive sensor assembly 124 for electronic device 100 (see, FIG. 4D) undergoing various operations that may be performed in accordance with process 200 of FIG. 3. It is understood that similarly numbered components may function in a substantially similar fashion. Redundant explanation of these components has been omitted for clarity.

As shown in FIG. 4A, silicone layer 130 may be coupled or bonded to a portion of bottom portion or component 126 of housing 102. Silicone layer 130 may be coupled or bonded to bottom portion or component 126 using a variety of bonding techniques. In a non-limiting example, silicone material forming silicone layer 130 may be injection molded onto bottom portion or component 126 of housing 102. In another non-limiting example, silicone layer may be die-cut to shape and subsequently installed or positioned on bottom portion or component 126 of housing 102. The die-cut silicone layer 130 may be positioned on bottom portion or component 126 in a uncured state. Silicone layer 130 may be subsequently cured to bottom portion or component 126 immediately after being positioned on housing 102, or during a subsequent curing process involving silicone layer 130 and distinct layers of capacitive sensor assembly 124, as discussed herein. The coupling or bonding of silicone layer 130 to bottom portion or component 126 shown in FIG. 4A may correspond to operation 202 in FIG. 2.

FIG. 4B shows first electrical trace 136 positioned within flex layer 132 positioned over silicone layer 130. First electrical trace 136 may be positioned within flex layer 132 using a variety of techniques. In a non-limiting example, a portion of the material forming flex layer 132 may be deposited over silicone layer 130 using any suitable material deposition technique, and first electrical trace may be positioned over the portion of flex layer 132 deposited on silicone layer 130. Subsequent to positioning first electrical trace 136 on the deposited portion of the material forming flex layer 132, the remaining material used to form flex layer 132 may be deposited over first electrical trace 136. In another non-limiting example, flex layer 132 may be formed over silicone layer 130, and a trench may be formed in a portion of flex layer 132 to receive first electrical trace 136. In the non-limiting example, first electrical trace 136 may be positioned within the trench, and additional material used to form flex layer 132 may fill in the remaining portion of the trench. The positioning of first electrical trace 136 within flex layer 132 shown in FIG. 4B may correspond to operation 204 in FIG. 2.

FIG. 4B may also show silicone layer 130 cured to flex layer 132 including first electrical trace 136. In a non-limiting example, housing 102, silicone layer 130 and flex layer 132 including first electrical trace 136 may undergo a curing process to cure or bond silicone layer 130 to flex layer 132. Additionally, and as discussed herein with respect to FIG. 4A, silicone layer 130 may undergo the curing process to cure or bond silicone layer 130 to bottom portion or component 126 of housing 102. The curing of silicone layer 130 to flex layer 132 including first electrical trace 136 shown in FIG. 4B may correspond to operation 206 in FIG. 2.

FIG. 4C shows an adhesive 134 applied to flex layer 132. In the non-limiting example shown in FIG. 4C, adhesive 134 may be applied to the entire exposed surface of flex layer 132 to ensure a desired bond is achieved between flex layer 132 and subsequent components of electronic device 100 (e.g., cover 112). As discussed herein, adhesive 134 may be a pressure sensitive adhesive. Additionally, adhesive 134 may take the form of any medium associated with adhesives including, but not limited to, tape, spray and paste. The applying of adhesive 134 to flex layer 132 shown in FIG. 4C may correspond to operation 208 in FIG. 2.

FIG. 4D shows cover 112 adhered to flex layer 132 using adhesive 134. In the non-limiting example shown in FIG. 4D, intermediate layer 118 formed on inner surface 120 of cover 112 may be coupled directly to adhesive 134 to couple cover 112 to flex layer 132. Where adhesive 134 is formed as a pressure sensitive adhesive, cover 112 may be pressed into adhesive 134 to form the bond and/or to adhere cover 112 to flex layer 132. By adhering cover 112 to flex layer 132 using adhesive 134, a hermetic seal may be formed within electronic device 100 between cover 112, housing 102 and the various layers and components of capacitive sensor assembly 124. The hermetic seal may prevent debris, such as dust or water, from entering electronic device 100 and causing damage to the internal components of electronic device 100. The adhering of the cover 112 to flex layer 132 using adhesive 134 shown in FIG. 4D may correspond to operation 210 in FIG. 2.

FIG. 5 depicts an enlarged cross-section front view of a portion of electronic device 100 of FIG. 1 taken along line CS-CS, according to another embodiment. Electronic device 100 shown in FIG. 5 includes a capacitive sensor assembly 324 having a distinct configuration from capacitive sensor assembly 124 discussed herein with respect to FIGS. 2-4D. It is understood that similarly numbered and/or named components of electronic device 100 and capacitive sensor assembly 324 may function in a substantially similar fashion. Redundant explanation of these components has been omitted for clarity.

As shown in FIG. 5, and as similarly discussed herein with respect to FIG. 2, first electrical trace 336 may be positioned or formed within flex layer 332. However, distinct from first electrical trace 136 of FIG. 2, first electrical trace 336, and flex layer 332, may be positioned between silicone layer 330 and bottom portion or component 126 of housing 102. As shown in the non-limiting example of FIG. 5, flex layer 332 may be coupled to bottom portion or component 126 of housing 102 using adhesive 334. Additionally, flex layer 332 including first electrical trace 336 may be coupled or cured to silicone layer 330 of capacitive sensor assembly 324. As a result of the position of flex layer 332 in capacitive sensor assembly 324, and distinct from capacitive sensor assembly 124 of FIG. 2, silicone layer 330 may be directly coupled to or cured to intermediate layer 118 formed on inner surface 120 of cover 112.

Also distinct from capacitive sensor assembly 124 of FIG. 2, capacitive sensor assembly 324 may include a second electrical trace 338. In the non-limiting example shown in FIG. 5, second electrical trace 338 may be positioned within intermediate layer 118 formed on inner surface 120 of cover 112. Additionally, second electrical trace 338 may be positioned between silicone layer 330 and cover 112, and may also be positioned adjacent silicone layer 330, opposite first electrical trace 336 positioned within flex layer 332. Similar to first electrical trace 336, second electrical trace 338 may have capacitive characteristics and/or second electrical trace 338 may be formed from an electrically conductive material, for example copper. Although only a single first electrical trace 336 and second electrical trace 338 are shown in FIG. 5, it is understood that one or both of the electrical traces of capacitive sensor assembly 324 may include a group of electrical traces forming first electrical trace(s) 336 and/or second electrical trace(s) 338.

As discussed herein, second electrical trace 338 may be positioned or formed within intermediate layer 118 using any suitable laser etching processes. In a non-limiting example, and discussed in detail herein, a laser etching process used to form second electrical trace 338 may include a laser direct structuring (LDS) process. As a result of using an LDS process, intermediate layer 118 may be formed from a thermoplastic material that may be doped with metal-plastic additives.

Second electrical trace 338 of capacitive sensor assembly 324 may be a driven capacitive trace that may cooperate with first electrical trace 336 to detect a force applied to cover 112 by measuring changes in capacitance between the first electrical trace 336 and second electrical trace 338, as discussed herein. In the non-limiting example shown in FIG. 5, where second electrical trace 338 is a driven capacitive trace, first electrical trace 336 may be a sense capacitive trace that may cooperate with second electrical trace 338. As similarly discussed herein with respect to first electrical trace 136 and bottom portion or component 126 in FIG. 2, first electrical trace 336 and second electrical trace 338 of capacitive sensor assembly 324 may be utilized within electronic device 100 to detect a force applied to cover 112 by measuring a change in capacitance between the respective electrical traces 336, 338.

As a result of capacitive sensor assembly 324 including second electrical trace 338, bottom portion or component 126 of housing 102 may not be required to cooperate with first electrical trace 336 in order to measure a change in capacitance. As such, housing 102, and specifically, bottom portion or component 126 may be formed from any suitable material for electronic device, and may not necessarily be formed from a material having electrically conductive properties.

FIG. 6 depicts an example process for forming a capacitive sensor assembly for an electronic device. Specifically, FIG. 6 is a flowchart depicting one example process 400 for forming a capacitive sensor assembly having cooperating electrical traces formed from a first electrical trace and a second electrical trace. In some cases, process 400 may be used to form one or more capacitive sensor assemblies, as discussed above with respect to FIG. 5.

In operation 402, an intermediate layer may be coupled to an inner surface of a cover for an electronic device. In operation 404, a portion of the intermediate layer may be etched to form an electrical trace. In operation 406, a distinct electrical trace positioned within a flex layer is bonded to the intermediate layer using a silicone layer. In operation 408, an adhesive may be applied to the flex layer including the distinct electrical trace. In operation 410, a bottom portion or component of the housing may be adhered to the flex layer using the applied adhesive.

FIGS. 7A-7D show capacitive sensor assembly 324 for electronic device 100 (see, FIGS. 7C and 7D) undergoing various operations that may be performed in accordance with process 400 of FIG. 6. It is understood that similarly numbered components may function in a substantially similar fashion. Redundant explanation of these components has been omitted for clarity.

As shown in FIG. 7A, intermediate layer 118 may be coupled to inner surface 120 of cover 112. Intermediate layer 118 may be formed from a variety of materials, and as such, may be coupled and/or applied to cover 112 using various techniques. In a non-limiting example, intermediate layer 118 may be formed from an ink material. The ink material may be deposited on inner surface 120 of cover 112 using any suitable deposition technique or process including, but not limited to, painting, spraying, mask-and-ink submersion and the like. In another non-limiting example, intermediate layer 118 may be formed as a substantially solid material layer. In the non-limiting example, the substantially solid material layer may be formed as a plastic layer that may be coupled to inner surface 120 of cover 112. The plastic layer may be coupled to the inner surface 120 using any suitable coupling technique or process (e.g., bonding, welding, melting, and so on). Furthermore, and as discussed in detail with respect to FIG. 7B, intermediate layer 118 may be formed from a thermoplastic material that may be doped with metal-plastic additives. The metal-plastic additives may be activated and/or react when exposed to a laser beam. The coupling of intermediate layer 118 to inner surface 120 of cover 112 shown in FIG. 7A may correspond to operation 402 in FIG. 6.

FIG. 7B shows intermediate layer 118 having undergone an etching process to form second electrical trace 338. Various etching processes may be performed on intermediate layer 118 to form second electrical trace 338. In a non-limiting example, intermediate layer 118 may undergo a laser direct structuring (LDS) process. During the LDS process, a portion of intermediate layer 118, formed from thermoplastic material having doped metal-plastic additives, may be exposed to a laser. The laser may cause the metal-plastic additives to react or activate, which may result in the exposed portions of intermediate layer 118 to change in chemical composition. The intermediate layer 118 may be subsequently dunked in a bath of a metal material (e.g., copper), where the exposed portions of intermediate layer 118 may attract the metal material to form second electrical trace 338. In another non-limiting embodiment, intermediate layer 118 may be masked and subsequently etched to form a trench in a portion of intermediate layer 118. Conductive material (e.g., copper) may then be deposited within the trench formed in intermediate layer 118 to form second electrical trace 338. The etching of intermediate layer 118 to form second electrical trace 338 shown in FIG. 7B may correspond to operation 404 in FIG. 6.

FIG. 7C shows flex layer 332 including first electrical trace 336 coupled or bonded to intermediate layer 118 via silicone layer 330. That is, flex layer 332 may be coupled or bonded to silicone layer 330, and intermediate layer 118 may also be coupled or bonded to silicone layer 330 opposite flex layer 332. In the non-limiting example, silicone layer 330 may be coupled or bonded to intermediate layer 118 including second electrical trace 338 using a variety of bonding techniques. In a non-limiting example, silicone material forming silicone layer 330 may be injection molded onto intermediate layer 118. In another non-limiting example, silicone layer 330 may be die-cut to shape and subsequently installed or positioned on intermediate layer 118. The die-cut silicone layer 330 may be positioned on intermediate layer 118 in a uncured state. Silicone layer 330 may be subsequently cured to intermediate layer 118 immediately after being positioned on intermediate layer 118, or during a subsequent curing process involving silicone layer 330 and distinct layers of capacitive sensor assembly 324, as discussed herein.

As similarly discussed herein with respect to FIG. 4B, first electrical trace 336 may be positioned within flex layer 332 using a variety of techniques. In a non-limiting example, a portion of the material forming flex layer 332 may be deposited over silicone layer 330 using any suitable material deposition technique, and first electrical trace 336 may be positioned over the portion of flex layer 332 deposited on silicone layer 330. Subsequent to positioning first electrical trace 336 on the deposited portion of the material forming flex layer 332, the remaining material used to form flex layer 332 may be deposited over first electrical trace 336. In another non-limiting example, flex layer 332 may be formed over silicone layer 330, and a trench may be formed in a portion of flex layer 332 to receive first electrical trace 336. In the non-limiting example, first electrical trace 336 may be positioned within the trench, and additional material used to form flex layer 332 may fill in the remaining portion of the trench.

Additionally, and also discussed herein with respect to FIG. 4B, silicone layer 330 may be cured to flex layer 332 including first electrical trace 336. In a non-limiting example, cover 112, intermediate layer 118, silicone layer 330 and flex layer 332 including first electrical trace 336 may undergo a curing process to cure or bond silicone layer 330 to flex layer 332. Silicone layer 330 may undergo the curing process to cure or bond silicone layer 330 to intermediate layer 118 formed on cover 112. The coupling or bonding of flex layer 332 and/or silicone layer 330 to intermediate layer 118 shown in FIG. 7C may correspond to operation 406 in FIG. 6.

FIG. 7C may also show an adhesive 334 applied to flex layer 332. In the non-limiting example shown in FIG. 7C, adhesive 334 may be applied to the entire exposed surface of flex layer 332 to ensure a desired bond is achieved between flex layer 332 and subsequent components of electronic device 100 (e.g., bottom portion or component 126 of housing 102). As discussed herein, adhesive 334 may be a pressure sensitive adhesive. Additionally, adhesive 334 may take the form of any medium associated with adhesives including, but not limited to, tape, spray and paste. The applying of adhesive 334 to flex layer 332 shown in FIG. 7C may correspond to operation 408 in FIG. 6.

FIG. 7D shows bottom portion or component 126 of housing 102 adhered to flex layer 332 using adhesive 334. In the non-limiting example shown in FIG. 7D, bottom portion or component 126 may be coupled directly to adhesive 334 to couple housing 102 to flex layer 332. Where adhesive 334 is formed as a pressure sensitive adhesive, bottom portion or component 126 may be pressed into adhesive 334 to form the bond and/or to adhere housing 102 to flex layer 332. By adhering housing 102 to flex layer 332 using adhesive 334, a hermetic seal may be formed within electronic device 100 between cover 112, housing 102 and the various layers and components of capacitive sensor assembly 324. The adhering of the bottom portion or component 126 of housing 102 to flex layer 332 using adhesive 334 shown in FIG. 7D may correspond to operation 410 in FIG. 6.

FIG. 8 depicts an enlarged cross-section front view of a portion of electronic device 100 of FIG. 1 taken along line CS-CS, according to a further embodiment. Electronic device 100 shown in FIG. 8 includes a capacitive sensor assembly 524 having a distinct configuration from capacitive sensor assembly 124, 324 discussed herein with respect to FIGS. 2-4D, and 5-7D, respectively. It is understood that similarly numbered and/or named components of electronic device 100 and capacitive sensor assembly 524 may function in a substantially similar fashion. Redundant explanation of these components has been omitted for clarity.

As shown in FIG. 8, and as similarly discussed herein with respect to FIG. 5, an electrical trace of capacitive sensor assembly 524 may formed in intermediate layer 118 formed on inner surface 120 of cover 112. In the non-limiting example shown in FIG. 8, first electrical trace 536 may be formed in intermediate layer 118. Similar to capacitive sensor assembly 124 of FIG. 2, and dissimilar to capacitive sensor assembly 324 of FIG. 5, capacitive sensor assembly 524 may not include a second, distinct electrical trace formed between cover 112 and housing 102. As such, and as similarly discussed herein with respect to FIG. 2, bottom portion or component 126 of housing 102 may be formed from an electrically conductive material and may act as a cooperating electrical trace for first electrical trace 536 positioned within intermediate layer 118. First electrical trace 536 positioned within intermediate layer 118 and bottom portion or component 126 of housing 102 may detect a force applied to cover 112 by measuring a change in capacitance between electrical trace 536 and bottom portion or component 126, as discussed herein with respect to FIG. 2. Redundant explanation of these functions have been omitted for clarity.

Dissimilar to capacitive sensor assembly 124 of FIG. 2 and capacitive sensor assembly 324 of FIG. 5, capacitive sensor assembly 524 of FIG. 8 may not include a flex layer (e.g., flex layer 132—FIG. 2; flex layer 332—FIG. 5). In the non-limiting example where first electrical trace 536 is positioned within intermediate layer 118 and bottom portion or component 126 act as a cooperating electrical trace for first electrical trace 536, flex layer may be removed from capacitive sensor assembly 524. Additionally, because the flex layer may be removed from capacitive sensor assembly 524, the adhesive layer used to bond the flex layer to intermediate layer 118 (e.g., adhesive 134—FIG. 2) or housing 102 (e.g., adhesive 334—FIG. 5) may also be removed from capacitive sensor assembly 524. The removal of the flex layer and the adhesive layer may reduce the number of layers and the height of capacitive sensor assembly 524. Additionally, the removal of the flex layer and the adhesive layer from capacitive sensor assembly 524 may reduce the overall size and/or height of electronic device 100 as well.

Silicone layer 530 may be coupled to intermediate layer 118 and housing 102. In a non-limiting example shown in FIG. 8, and distinct from silicone layers 130, 330 in FIGS. 2 and 5, respectively, silicone layer 530 may be coupled, bonded and/or cured to intermediate layer 118 formed on inner surface 120 of cover 112, and bottom portion or component 126 of housing 102. As such, silicone layer 530 may be the only compliant layer formed between first electrical trace 536 and bottom portion or component 126, as the flex layer and the adhesive layer have been removed from capacitive sensor assembly 524.

FIG. 9 depicts an example process for forming a capacitive sensor assembly for an electronic device. Specifically, FIG. 9 is a flowchart depicting one example process 600 for forming a capacitive sensor assembly having cooperating electrical traces formed from a first electrical trace and an electrically conductive housing. In some cases, process 600 may be used to form one or more capacitive sensor assemblies, as discussed above with respect to FIG. 8.

In operation 602, an intermediate layer may be coupled to an inner surface of a cover for an electronic device. In operation 604, a portion of the intermediate layer may be etched to form an electrical trace. In operation 606, a silicone layer may be cured to the intermediate layer and a bottom portion or component of a housing for the electronic device.

FIGS. 10A-10C show capacitive sensor assembly 524 for electronic device 100 (see, FIG. 10C) undergoing various operations that may be performed in accordance with process 600 of FIG. 9. It is understood that similarly numbered components may function in a substantially similar fashion. Redundant explanation of these components has been omitted for clarity.

As shown in FIG. 10A, intermediate layer 118 may be coupled to inner surface 120 of cover 112. Intermediate layer 118 may be formed from a variety of materials, and as such, may be coupled and/or applied to cover 112 using various techniques. In a non-limiting example, intermediate layer 118 may be formed from an ink material. The ink material may be deposited on inner surface 120 of cover 112 using any suitable deposition technique or process including, but not limited to, painting, spraying, mask-and-ink submersion and the like. In another non-limiting example, intermediate layer 118 may be formed as a substantially solid material layer. In the non-limiting example, the substantially solid material layer may be formed as a plastic layer that may be coupled to inner surface 120 of cover 112. The plastic layer may be coupled to the inner surface 120 using any suitable coupling technique or process (e.g., bonding, welding, melting, and so on). Furthermore, and as discussed in detail with respect to FIG. 7B, intermediate layer 118 may be formed from a thermoplastic material that may be doped with metal-plastic additives. The metal-plastic additives may be activated and/or react when exposed to a laser beam. The coupling of intermediate layer 118 to inner surface 120 of cover 112 shown in FIG. 10A may correspond to operation 602 in FIG. 9.

FIG. 10B shows intermediate layer 118 having undergone an etching process to form first electrical trace 536. Various etching processes may be performed on intermediate layer 118 to form first electrical trace 536. In a non-limiting example, intermediate layer 118 may undergo a laser direct structuring (LDS) process. During the LDS process, a portion of intermediate layer 118, formed from thermoplastic material having doped metal-plastic additives, may be exposed to a laser. The laser may cause the metal-plastic additives to react or activate, which may result in the exposed portions of intermediate layer 118 to change in chemical composition. The intermediate layer 118 may be subsequently dunked in a bath of a metal material (e.g., copper), where the exposed portions of intermediate layer 118 may attract the metal material to form first electrical trace 536. In another non-limiting embodiment, intermediate layer 118 may be masked and subsequently etched to form a trench in a portion of intermediate layer 118. Conductive material (e.g., copper) may then be deposited within the trench formed in intermediate layer 118 to form first electrical trace 536. The etching of intermediate layer 118 to form first electrical trace 536 shown in FIG. 10B may correspond to operation 604 in FIG. 9.

As shown in FIG. 10C, silicone layer 530 may be coupled, bonded or cured to a portion of intermediate layer 118 formed on cover 112 and bottom portion or component 126 of housing 102. Silicone layer 530 may be coupled, bonded or cured to intermediate layer 118 and housing 102 using a variety of bonding techniques. In a non-limiting example, silicone material forming silicone layer 530 may be injection molded between intermediate layer 118 or bottom portion or component 126 of housing 102. In another non-limiting example, silicone layer may be die-cut to shape and subsequently installed or positioned on intermediate layer 118 or bottom portion or component 126 of housing 102. The die-cut silicone layer 130 may be in an uncured state. Subsequent to positioning the die-cut silicone layer 530, cover 112 including intermediate layer 118, bottom portion or component 126 of housing 102 and silicone layer 530 may all undergo a curing process. The coupling, bonding or curing of silicone layer 530 to intermediate layer 118 and bottom portion or component 126 shown in FIG. 10C may correspond to operation 606 in FIG. 9.

Although discussed herein as a bottom portion or component of the external housing of the electronic device, it is understood that bottom portion or component 126 may not be a portion of housing 102, and/or may not be external component of electronic device 100. In another non-limiting example, bottom component 126 may be a bottom component of the capacitive sensor assembly, and may be an internal component or structure positioned within opening 122 formed between cover 112 and housing 102. Additionally, cover may not include an external component of electronic device 100, and/or may not be substantially transparent. Similar to bottom component 126, cover 112 may be a top component of the capacitive sensor assembly, and may be an internal component or structure positioned within opening 122 formed between cover 112 and housing 102.

The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not target to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings. 

We claim:
 1. An electronic device, comprising: a housing, comprising: a top portion; and a bottom portion coupled to the top portion; and a capacitive sensor assembly positioned within the housing, the capacitive sensor comprising: a silicone layer coupled to the bottom portion of the housing; a flex layer coupled to the silicone layer opposite the bottom portion; and an electrical trace positioned within the flex layer and capacitively coupled with an electrically conductive region of the bottom portion, wherein the capacitive sensor assembly is configured to generate a signal responsive to a change in a capacitance between the electrical trace and the electrically conductive region.
 2. The electronic device of claim 1, wherein both the flex layer and the electrical trace of the capacitive sensor assembly are positioned between the top portion of the housing and the silicone layer.
 3. The electronic device of claim 2, wherein the capacitive sensor assembly further comprises an adhesive positioned between the flex layer and top portion of the housing, the adhesive bonding the flex layer to top portion of the housing.
 4. The electronic device of claim 2, wherein the silicone layer of the capacitive sensor assembly is coupled directly to the bottom portion of the housing.
 5. The electronic device of claim 1, further comprising: an intermediate layer positioned between the top portion of the housing and the silicone layer.
 6. The electronic device of claim 5, wherein the silicone layer of the capacitive sensor assembly is coupled directly to the intermediate layer.
 7. An electronic device, comprising: a housing; a cover glass at least partially positioned within an opening of the housing; an intermediate layer formed on an inner surface of the cover glass and configured to visually obscure an interior volume of the housing; and a capacitive sensor assembly positioned within the interior volume of the housing and comprising: a silicone layer positioned below the intermediate layer; and an electrical trace positioned within the intermediate layer, wherein the capacitive sensor assembly is configured to detect a change in capacitance between the electrical trace and another internal component of the electronic device.
 8. The electronic device of claim 7, wherein the another internal component of the electronic device is an electrically conductive inner surface of the housing.
 9. The electronic device of claim 8, wherein the silicone layer of the capacitive sensor is coupled to the housing.
 10. The electronic device of claim 7, wherein: the electrical trace is a first electrical trace; the capacitive sensor assembly further comprises a flex layer positioned between the silicone layer and the housing; and the another component of the electronic device is a second electrical trace positioned within the flex layer.
 11. The electronic device of claim 10, wherein the capacitive sensor assembly further comprises an adhesive positioned between the flex layer and the housing, the adhesive bonding the flex layer to the housing.
 12. An electronic device, comprising: a housing defining an opening and an internal surface forming a first electrical trace; a transparent layer positioned at least partially within the opening and defining an input surface; an opaque layer positioned on an underside of the transparent layer; a capacitive sensor assembly positioned below the transparent layer and along the internal surface of the housing, the capacitive sensor assembly including a second electrical trace separated from the first electrical trace by a deformable component, wherein the transparent layer is operative to compress the capacitive sensor assembly and move the first electrical trace and the second electrical trace toward one another, thereby triggering a switch event.
 13. The electronic device of claim 12, wherein the capacitive sensor assembly is configured to trigger the switch event using a change in capacitance measured between the first electrical trace and the second electrical trace.
 14. The electrical device of claim 12, wherein the capacitive sensor assembly further comprises: an adhesive layer positioned above the deformable component and adhered to the opaque layer; and a silicon layer positioned between the deformable component and the support structure.
 15. The electronic device of claim 12, wherein: the capacitive sensor assembly comprises a silicon layer positioned below the deformable component and the opaque layer; and the deformable component is adhered to the internal surface via an adhesive layer.
 16. The electronic device of claim 12, wherein the opaque layer is formed from an ink. 